Method of making a scratch-and etch-resistant coated glass article

ABSTRACT

A method of making a scratch resistant coated article which is also resistant to attacks by at least some fluorine-inclusive etchant(s) for at least a period of time is provided. In certain example embodiments, an anti-etch layer(s) is provided on a glass substrate in order to protect the glass substrate from attacks by fluorine-inclusive etchant(s), a scratch resistant layer of or including DLC is provided over the anti-layer(s), and a seed layer is provided between the anti-layer(s) and the scratch resistant layer so as to facilitate the adhesion of the scratch resistant layer while also helping to protect the anti-layer(s). Optionally, a base layer(s) or underlayer(s) may be provided under at least the anti-etch layer(s).

CROSS-REFERENCES TO APPLICATIONS

This application incorporates by reference the entire content of each ofapplication Ser. No. 10/996,044, filed Nov. 24, 2004, which is acontinuation-in-part (CIP) of application Ser. No. 10/899,305, filedJul. 27, 2004, and a CIP of application Ser. No. 10/989,721, filed Nov.17, 2004, as well as Application Ser. Nos. 60/529,624, filed Dec. 16,2003, and 60/529,103, filed Dec. 15, 2003.

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to a coated articleincluding a coating supported by a glass substrate. The coating includesan anti-etch layer that is resistant (e.g., resistant to fluoride-basedetchant(s)), and may also include other layer(s) such as ascratch-resistant layer comprising diamond-like carbon (DLC). Coatedarticles according to different embodiments of this invention may beused as windows or in any other suitable application.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Unfortunately, vandals have increasingly been turning to glass etchantsas a tool of choice for graffiti. For example, graffiti on glass windowsof subway cars is commonplace. Vandals have been forming such graffition windows of subway cars, buildings, trains, buses and other glasswindows by using glass etchants which are capable of etching glass atlocations where such etchants are applied.

Armor-etch is an example of a bifluoride salt (e.g., ammonia bifluorideor sodium bifluoride) based paste used for etching patterns on glasssurfaces, and has been used in forming graffiti. The mechanism offluoride ion attack on SiO₂ of glass is summarized below for purposes ofexample only and understanding.

Though hydrogen fluoride (HF) does not dissociate well, active hydrogenfluoride paste reacts with silicate (which forms the matrix for glass)in the presence of water as in the following equations:HF₂—=HF+F—6HF+SiO₂=H₂SiF₆+2H₂O

An alternative type of glass etching material, which is also abi-fluoride based etchant, is sometimes referred to as B&B etching crèmemanufactured by B&B Etching Products. Ammonium bifluoride ((NH₄)HF₂) andsodium bifluoride (NaHF₂) salts are very soluble in water. For example,a 2.8 g/100 g solution of ammonium fluoride would produce a 1.7 g/100 gsolution of hydrofluoric acid (HF) at pH 1, with 85% of the fluorineatoms in the form of HF. At higher concentrations or higher pH, asignificant amount of the HF₂ ⁻ ion is present. Acidified fluorides canproduce substantial quantities of HF in solution.

The active ammonia bi-fluoride reacts with silicate in the presence ofwater as presented in the following equations:(NH₄)HF₂=(NH₄)++HF_(2—)HF_(2—)=HF+F—6HF+SiO₂=H₂SiF₆+2H₂O

An equilibrium is established between the reactants and products. Thus,as hydrogen fluoride is consumed in reacting with the SiO₂ of the glass,more hydrogen fluoride is produced to maintain the equilibrium. The SiO₂etch rate (i.e., the etch rate of the glass) is linearly related to theHF— and HF²⁻ concentrations, and is not related to the F— concentrationat any pH.

Conventional coatings used for fluoride resistance to protect glass fromsuch etchings are polymer-based film. Unfortunately, these coatings aresusceptible to damage and are not scratch resistant thereby renderingtheir use in environments such as subway cars, buses and vehiclesundesirable. Moreover, in some cases the film can be lifted and theetchant applied under the film.

Scratch resistant coated glass articles are known which utilize alayer(s) comprising diamond-like carbon (DLC) on the glass surface. Forexample, see U.S. Pat. Nos. 6,261,693, 6,303,226, 6,280,834, 6,284,377,6,447,891, 6,461,731, 6,395,333, 6,335,086, and 6,592,992, thedisclosures of which are all hereby incorporated herein by reference.While carbon is resistant to fluoride ion (and HF₂—) attack, theselayers when formed via ion beam deposition techniques at very smallthicknesses give rise to micro-particulates on the substrate. When suchlayers are very thin in nature, these micro-particles may give rise topinholes which are pathways for the HF to attack the underlying glass.Thus, scratch resistant coated articles which utilize only a layercomprising DLC on the glass are sometimes susceptible to the fluoridebased etchant attacks described above.

In view of the above, it can be seen that there exists a need in the artfor a scratch resistant coated article which is also resistant toattacks by fluoride-based etchant(s).

A scratch resistant coated article is provided which is also resistantto attacks by at least some etchants (e.g., fluoride-based etchant(s))for at least a period of time. In certain example embodiments, ananti-etch layer(s) is provided on the glass substrate in order toprotect the glass substrate from attacks by fluoride-based etchant(s).In certain example embodiments, the anti-etch layer(s) is substantiallytransparent to visible light.

In certain example embodiments of this invention, the anti-etch layermay be provided on the substrate over an underlayer(s) of a dielectricmaterial. In certain example embodiments, the dielectric underlayer maybe formed using flame pyrolysis in an atmosphere at or close toatmospheric pressure. The use of flame pyrolysis to form theunderlayer(s) is advantageous in that the layer(s) formed using flamepyrolysis may be formed in an ambient atmosphere which need not be at apressure less than atmospheric (as opposed to sputtering for examplewhich is typically formed in a chamber at a low pressure less thanatmospheric). Thus, expensive sputtering or other low-pressuredeposition systems need not be used to form this particular layer(s).Moreover, another example advantage is that such an underlayer depositedvia flame pyrolysis has been found to further improve the etchresistance of the coated article by removing or reducing chemical orother defects on the glass surface. In particular, it is believed thatthe flame-pyrolysis deposited underlayer removes or reduces chemicaldefects on the surface on which the anti-etch layer is directlyprovided. Such defects may lead to growth defects in the anti-etch layer2 which can be weak points more susceptible to etchant attack. Thus, theremoval or reduction of such defects via the use of the flame pyrolysisdeposited underlayer is advantageous in that etch resistance can besurprisingly improved.

In certain example embodiments, the anti-etch layer may be provided onthe glass substrate, along with an overlying scratch resistant layer ofor including diamond-like carbon (DLC). The anti-etch layer may be of orinclude any suitable material such as, for example, the material(s)discussed herein.

In certain example embodiments, the anti-etch layer(s) may comprise orconsist essentially of zirconium oxycarbide, hydrogenated zirconiumoxycarbide, tin oxycarbide, or hydrogenated tin oxycarbide. In certainexample embodiments, the optional underlayer(s) may comprise or consistessentially of silicon oxide, silicon nitride, and/or the like.

In certain example embodiments, there is provided a method of making acoated article, the method comprising providing a glass substrate; usingflame pyrolysis to deposit at least one layer on the glass substrate;and forming an anti-etch layer on the glass substrate over the flamepyrolysis deposited layer.

In other example embodiments of this invention, there is provided acoated article comprising a substrate; an underlayer comprising siliconoxide on the substrate; and an anti-etch layer comprising at least onematerial selected from the group consisting of: zirconium oxycarbide,tin oxycarbide, indium oxide and cerium oxide; and wherein the anti-etchlayer is on the substrate over at least the underlayer comprisingsilicon oxide, and wherein the anti-etch layer is resistant to at leastsome fluoride-based glass etchants.

In certain example embodiments, a method of making a coated article isprovided. A glass substrate is provided. An anti-etch layer is formed onthe glass substrate, with the anti-etch layer comprising at least one offluorine-doped tin oxide and cerium oxide. A scratch-resistant layercomprising diamond-like carbon (DLC) is ion beam deposited on the glasssubstrate over the anti-etch layer. A seed layer is formed between theanti-etch layer and the layer comprising DLC, with the seed layerfacilitating adhesion of the layer comprising DLC and/or protecting theanti-etch layer from damage during the ion beam depositing of the layercomprising DLC.

In certain example embodiments, a method of making a coated article isprovided. A glass substrate is provided. A base layer or underlayer isformed on the glass substrate. An anti-etch layer is formed over thebase layer or underlayer, with the anti-etch layer comprising at leastone of fluorine-doped tin oxide and cerium oxide. A layer comprisingdiamond-like carbon (DLC) is ion beam deposited on the glass substrateover the anti-etch layer. A seed layer is formed between the anti-etchlayer and the layer comprising DLC, with the seed layer comprisingsilicon nitride.

In certain example embodiments, a coated article is provided. The coatedarticle comprises a glass substrate; an anti-etch layer formed on theglass substrate, with the anti-etch layer comprising fluorine-doped tinoxide and/or cerium oxide; an ion beam deposited scratch-resistant layercomprising diamond-like carbon (DLC) on the glass substrate over theanti-etch layer; and a seed layer provided between the anti-etch layerand the layer comprising DLC, with the seed layer cooperating with thelayer comprising DLC to facilitate adhesion of the layer comprising DLCand/or to protect the anti-etch layer from damage during the ion beamdepositing of the layer comprising DLC.

The features, aspects, advantages, and example embodiments describedherein may be combined to realize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages will be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIG. 1 is a cross sectional view of a coated article according to anexample embodiment;

FIG. 2 is a cross sectional view of a coated article according toanother example embodiment;

FIG. 3 is a cross sectional view of a coated article according toanother example embodiment;

FIG. 4 is a cross sectional view of a coated article according toanother example embodiment;

FIG. 5 is a cross sectional view of a coated article according toanother example embodiment;

FIG. 6 is a cross sectional view of a coated article according toanother example embodiment;

FIG. 7 is a schematic diagram illustrating an example method ofdepositing and/or forming an anti-etch layer according to an exampleembodiment of this invention;

FIG. 8 is a cross sectional view of a coated article according toanother example embodiment of this invention;

FIG. 9 is a flowchart listing certain example steps performed in makingthe coated article of FIG. 8 according to an example embodiment of thisinvention;

FIG. 10 is a cross sectional view of a coated article according toanother example embodiment of this invention;

FIG. 11 is a cross sectional view of a coated article according toanother example embodiment of this invention;

FIG. 12 is a cross sectional view of a coated article according toanother example embodiment of this invention;

FIG. 13 is a cross sectional view of a coated article according toanother example embodiment of this invention;

FIG. 14 is a cross sectional view of a coated article according toanother example embodiment of this invention; and

FIG. 15 is a flowchart listing certain example steps performed in makingthe coated article of FIG. 12 according to an example embodiment of thisinvention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Referring now more particularly to the accompanying drawings in whichlike reference numerals indicate like parts/layers throughout theseveral views.

Coated articles according to certain example embodiments of thisinvention may be used as subway car windows, transit bus windows, trainwindows, or other types of vehicle windows, or the like in differentapplications. Coated articles according to certain example embodimentsof this invention may also be used as architectural windows, inmonolithic or IG unit form. Coated articles such as windows according tocertain example embodiments of this invention may have a visibletransmission of at least about 15%, more preferably at least about 50%,more preferably of at least about 60%, and even more preferably of atleast about 70%. In certain example embodiments of this invention, anyof the coated articles discussed herein may or may not be heat treated(e.g., thermally tempered).

A scratch resistant coated article is provided which is also resistantto attacks by etchants (e.g., fluoride-based etchant(s)). In certainexample embodiments, an anti-etch layer(s) is provided on the glasssubstrate in order to protect the glass substrate from attacks byfluoride-based etchant(s). In certain example embodiments, the anti-etchlayer(s) is substantially transparent to visible light (e.g., theanti-etch layer if deposited alone would be transmissive to at leastabout 60% of visible light, more preferably at least about 70% ofvisible light, and even more preferably at least about 80% of visiblelight).

In certain example embodiments of this invention, in a multi-layerstack, a silicon oxide (e.g., SiO₂) base layer or underlayer is providedfor improving the fluoride etch protection of float glass or othersuitable substrate. The silicon oxide base layer may be from about 50 to1,500 Å thick, more preferably from about 100 to 1,000 Å thick, incertain example embodiments of this invention. The silicon oxide baselayer is located on the substrate, and may be located in direct contactwith the substrate or alternatively there may be layer(s) between thesubstrate and the silicon oxide layer. The silicon oxide inclusive baselayer may be produced by various methods, including MSVD and atmosphericpressure combustion chemical vapor deposition. Other layer(s) in thestack can include a relatively thick intermediate optically transparentlayer with inherent fluoride etch resistance, which may be called ananti-etch layer in certain example instances. The anti-etch layer may befrom about 500 to 5,000 Å thick in certain example embodiments. Theanti-etch layer may be of cerium oxide, indium oxide, zirconiumoxycarbide, or tin oxycarbide in certain example embodiments. On largearea products, the silicon oxide layer may be produced in a standardin-line MSVD coater, or alternatively by using one or more linearcombustion CVD burners that span the width of the glass substrate, withthe glass passing under the burners on a conveyor. For two sidedcoatings, the burners can be installed both above the glass and underthe glass between supporting rollers.

In certain example embodiments of this invention, single or multi-layercoatings according to example embodiments of this invention are able toresist HF attack on glass for twenty-four hours or so with no visiblesign of significant adverse effect. In example embodiments of thisinvention, such coatings have a dense structure, are characterized bylow pinhole density, and/or are characterized by substantial chemicalinertness (e.g., forming insoluble fluorides).

In certain example embodiments, the thickness of the anti-etch layer(see any layer 2 or 2′ herein) need not exceed about 0.9 μm (or 9,000Å). In certain example embodiments, the thickness of the anti-etch layer(2 or 2′) may be from about 50 to 9,000 Å, more preferably from100-5,000 Å. In certain preferred instances, the anti-etch layer (2 or2′) is preferably at least about 2,500 Å thick, and still morepreferably from about 3,000 to 5,000 Å thick. Although the anti-etchlayer may be thinner than this in certain example embodiments of thisinvention, if it is thinner than this then etch resistance may sufferundesirably. Moreover, when it is thicker than this range opticalproperties such as visible transmission or the like may suffer. However,it is noted that it is possible for the anti-etch layer to be thicker(e.g., from 9,000 to 20,000 Å) in certain instances.

FIG. 1 is a cross sectional view of a coated article according to anexample embodiment of this invention. The coated article includes aglass substrate 1 (e.g., soda lime silica glass, or borosilicate glasswhich may or may not be polished) which supports both an anti-etch layer2 and a scratch resistant layer 3 of or including DLC or the like.

The layer 3 of or including DLC may be any of the DLC inclusive layersdescribed in one or more of U.S. Pat. Nos. 6,261,693, 6,303,226,6,280,834, 6,284,377, 6,447,891, 6,461,731, 6,395,333, 6,335,086, and/or6,592,992, and may be deposited/formed in any of the manners describedin any of these patents, the disclosures of which are all incorporatedherein by reference. For example, and without limitation, DLC inclusivelayer 3 may be from about 5 to 1,000 angstroms (Å) thick in certainexample embodiments of this invention, more preferably from 10-300 Åthick. In certain example embodiments of this invention, layer 3including DLC may have an average hardness of at least about 10 GPa,more preferably at least about 20 GPa, and most preferably from about20-90 GPa. Such hardness renders layer(s) 3 resistant to scratching,certain solvents, and/or the like. Layer 3 may, in certain exampleembodiments, be of or include a special type of DLC known as highlytetrahedral amorphous carbon (t-aC), and may be hydrogenated (t-aC:H) incertain embodiments (e.g., from 5 to 39% hydrogen, more preferably from5 to 25% hydrogen, and most preferably from 5 to 20% hydrogen). Thistype of DLC includes more sp³ carbon-carbon (C—C) bonds than sp²carbon-carbon (C—C) bonds. In certain example embodiments, at leastabout 50% of the carbon-carbon bonds in the layer 3 may be sp³carbon-carbon (C—C) bonds, more preferably at least about 60% of thecarbon-carbon bonds in the layer 3 may be sp³ carbon-carbon (C—C) bonds,and most preferably at least about 70% of the carbon-carbon bonds in thelayer 3 may be sp³ carbon-carbon (C—C) bonds. In certain exampleembodiments of this invention, the DLC inclusive layer 3 may have adensity of at least about 2.4 gm/cm³, more preferably of at least about2.7 gm/cm³. Example linear ion beam sources that may be used to depositDLC inclusive layer 3 on substrate 1 via an ion beam include any ofthose in any of U.S. Pat. Nos. 6,359,388, 6,261,693, 6,002,208,6,335,086, 6, 303,226, or 6,303,225 (all incorporated herein byreference). When using an ion beam source to deposit layer(s) 3,hydrocarbon feedstock gas(es) (e.g., C₂H₂), HMDSO, or any other suitablegas, may be used in the ion beam source in order to cause the source toemit an ion beam toward substrate 1 for forming DLC inclusive layer(s)3. It is noted that the hardness and/or density of layer(s) 3 may beadjusted by varying the ion energy of the depositing apparatus. The useof DLC inclusive layer 3 allows the coated article (e.g., monolithicwindow, or IG unit) to be more scratch resistant than if the coatingwere not provided.

In certain example embodiments of this invention, the glass substrate 1may be ion beam milled before the anti-etch layer 2 (or layer 4) isdeposited thereon. The ion beam milling of the glass substrate has beenfound to remove certain defects on the glass surface thereby resultingin a more durable end product. For example and without limitation, anyof the example techniques of ion beam milling described in U.S. Pat. No.6,368,664 may be used to ion beam mill the glass substrate 1 in thisregard, the disclosure of the '664 being incorporated herein byreference. In the FIG. 1 embodiment, for example, after ion beam millingthe glass substrate (e.g., to remove at least about 2 Å of glass fromthe substrate, more preferably at least about 5 Å, and possibly at leastabout 10 Å), the anti-etch layer 2 may be deposited using magnetronsputtering or IBAD in different embodiments of this invention.Thereafter, the DLC inclusive layer 3 may be ion beam deposited over theanti-etch layer 2. Stack configurations may be produced by one-passin-line deposition in a suitably configured system, or in any othersuitable manner.

Anti-etch layer(s) 2 is provided to allow the coated article to beresistant to attacks by fluoride-based etchant(s) such as thosediscussed above. The anti-etch layer 2 may be deposited by sputtering,ion beam deposition, or ion beam assist deposition (IBAD) in differentembodiments of this invention. Anti-etch layer 2 substantially prevents(or reduces) fluoride-based etchant(s) such as those discussed abovefrom reaching the glass substrate 1 for at least a period of time (e.g.,for at least one hour, more preferably for at least twelve hours, andmost preferably for at least twenty-four hours), thereby rendering thecoated article more resistant to attacks by fluoride-based etchant(s)such as those discussed above. Moreover, since certain embodiments ofthis invention are used in the context of window applications, theanti-etch layer(s) 2 is substantially transparent to visible light.

It has been found that the inclusion of carbon into an inorganic layer 2or coating significantly improves the resistance of the coated glassarticle to corrosion by fluoride etching. In certain exampleembodiments, at least carbon inclusive reactive gas (e.g., acetylene(C₂H₂) and/or CO₂) is used during the deposition process of anti-etchlayer 2 in order to provide carbon in the resulting layer therebyimproving the corrosion resistance of the layer and the coated article.As shown in FIG. 1, the anti-etch layer 2 may comprise or consistessentially of zirconium oxycarbide (e.g., ZrOC), zirconium carbide(ZrC), hydrogenated zirconium oxycarbide (e.g., ZrOC:H), and/orhydrogenated zirconium carbide (e.g., ZrC:H). These materials areadvantageous in that zirconium carbide is very scratch resistant,thereby improving the mechanical durability of the coated article inaddition to being etch resistant. In this respect, zirconium carbide(even if it also includes oxygen) tends to be a very hard and durablematerial. In certain example embodiments of this invention, thezirconium carbide inclusive layer 2 may be formed (e.g., via sputteringor IBAD) so as to have an average hardness of at least about 20 GPa,more preferably of at least about 25 GPa, still more preferably of atleast about 27 GPa, and most preferably of at least about 29 GPa.

Moreover, another advantage associated with these materials is thatzirconium carbide (whether or not hydrogenated and/or oxided) is fairlyresistant to oxidation in environments where it is exposed to UV raysand/or water—this is an improvement over DLC alone in certain examplenon-limiting embodiments of this invention.

It has surprisingly been found that when Zr (or Sn as discussed below)is reactively sputter-deposited or otherwise deposited using a carboninclusive gas such as C₂H₂ plus O₂, or CO₂ (optionally in addition to Argas for example), the resulting coating and coated article realizessignificantly improved resistance to fluoride based etching compared toa situation where the Zr (or Sn) is reactively deposited using only O₂gas (in addition to Ar). It is believed that the surprisingly improvedresistance resulting from the inclusion of carbon in the gas and thusthe layer is due to the carbon's inert characteristics. While thesesurprisingly results are associated with Zr, the Zr may be replaced withany of the following materials in any layer 2 herein: Sn, Ti, Hf, V, Nbor Ta (it is expected that these surprisingly results will also beapplicable to these materials).

As mentioned above, the ZrC or ZrOC may be hydrogenated in certainexample embodiments of this invention. In hydrogenated embodiments(e.g., ZrC:H or ZrOC:H), the hydrogen content of the layer may be fromabout 1-40%, more preferably from about 5-35%, and even more preferablyfrom about 5-25%.

As explained above, when the DLC layer is provided, it is typicallydeposited by an ion beam technique over the Zr inclusive anti-etch layer2. In such instances, due to the high energy which may be used in ionbeam depositing DLC inclusive layer 3, the DLC may alloy with the Zr atthe interface between layers 2 and 3. Thus, a thin layer comprising analloy of Zr and DLC may be provided between layers 2 and 3 in certainexample embodiments of this invention.

FIG. 2 illustrates another example embodiment of this invention where anunderlayer 4 (e.g., silicon nitride, silicon oxide {e.g., SiO₂ or anyother suitable stoichiometry}, or silicon oxynitride) is providedbetween the glass substrate 1 and the anti-etch layer 2 discussed above.Of course, any of the aforesaid anti-etch layers 2 may be used as layer2 in this embodiment. In certain example instances, the underlayer 4(which is preferably a dielectric) has been found to further improve theetch resistance of the coated article by removing or reducing chemicalor other defects on the glass surface. In particular, it is believedthat the underlayer 4 of silicon oxide for example removes or reduceschemical defects on the surface on which the anti-etch layer is directlyprovided. Such defects may lead to growth defects in the anti-etch layer2 which can be weak points more susceptible to etchant attack. Thus, theremoval or reduction of such defects via the use of silicon oxide or thelike is advantageous in that etch resistance can be surprisinglyimproved. The silicon oxide or the like of the underlayer 4 may beformed in any suitable manner, such as by magnetron sputtering, flamepyrolysis (combustion-CVD), etc. An example advantage of flame pyrolysisor combustion-CVD is that it is an atmospheric pressure process and doesnot require expensive hardware typically associated with low pressureprocesses such as sputtering.

In certain example embodiments of this invention, any of the underlayers4 may have a thickness of from about 30 to 800 Å, more preferably fromabout 50 to 500 Å, and most preferably from about 100 to 400 Å.

FIG. 3 illustrates another example embodiment of this invention wherethe anti-etch layer 2 alone is provided on the glass substrate. Thereneed not be any protective layer over the anti-etch layer 2 in thisembodiment. Again, any of the aforesaid anti-etch layers 2 may be usedas layer 2 in this FIG. 3 embodiment. In other words, the anti-etchlayer 2 in the FIGS. 2-3 embodiments may be made of or include any ofthe materials listed above with respect to layer 2 in the FIG. 1embodiment.

It has been found that the deposition temperature for the anti-etchlayer 2 may in certain instances play a role in etch resistance. Incertain example instances, sputter-depositing anti-etch layer 2 atelevated temperatures results in unexpectedly improved etch resistance.In certain example embodiments, the anti-etch layer 2 (or 2′) isdeposited by sputtering onto a glass substrate 1 (with or without anunderlayer(s) 4 therebetween) at a temperature of at least about 100degrees C., more preferably of at least 200 degrees C., still morepreferably at least 300 degrees C., even more preferably of at least 400degrees C., and sometimes at least 450 degrees C. It is believed thatthe higher temperatures increase the energy provided during the layerformation process and increase the density of the layer therebyimproving anti-etch characteristics. However, in other exampleinstances, elevated temperatures are not used and the deposition maytake place at room temperature or the like.

As an alternative to using high temperatures when forming the anti-etchlayer, the anti-etch layer 2 may be formed using IBAD in certain exampleembodiments of this invention. Again, the advantage of using IBAD isthat the ion beam(s) used during IBAD layer formation adds energy to thelayer formation process and causes a more dense layer to be formed.Again, it is believed that this improves anti-etch characteristics ofthe layer 2. In an IBAD process, both an ion beam(s) and material from asputtering target(s) simultaneously impinge on the substrate in order toform the layer being deposited. FIG. 7 illustrates and example of usingIBAD to form/deposit anti-etch layer 2. As shown, in this IBADembodiment both an ion beam source(s) 26 and a sputtering deviceincluding a sputtering target(s) 50 are used. An ion beam B from the ionbeam source 26 intersects with the material M sputtered from thesputtering target(s) 50 proximate the surface where at least part of theanti-etch layer 2 (or 2′) is being grown, so that at least part of theanti-etch layer 2 is grown/formed by a simultaneous combination of boththe ion beam and sputtering. Substrate 1 is preferably moving indirection D during the layer formation process.

In a pure sputtering embodiment where anti-etch layer 2 (or 2′) isformed by sputtering only with no ion source, or alternatively in theFIG. 7 IBAD embodiment, gas including carbon such as gas comprising C₂H₂and/or CO₂ may be introduced to a sputtering chamber proximate thesputtering target 50 (e.g., of Zr, Sn or the like) so that a layer 2comprising ZrC:H and/or ZrC is formed on (directly or indirectly) thesubstrate 1. It will be appreciated that when it is desired tohydrogenate the layer, the gas should include hydrogen and may comprisea hydrocarbon gas for example (e.g., C₂H₂). In addition to the carboninclusive gas, gas(es) such as Ar and/or O₂ may also be introduced intothe sputtering chamber proximate target 50. When O₂ gas is alsointroduced in addition to C₂H₂ and/or CO₂ gas proximate the target 50,then a layer 2 comprising ZrOC:H and/or ZrOC is formed on (directly orindirectly) the substrate 1. An example gas introduction is 90 sccm ofAr gas and 20 sccm of C₂H₂ gas being introduced into the sputter zoneproximate the target 50. The sputter zone is typically at a pressureless than atmospheric pressure (e.g., at 2 to 3 mTorr). Moreover, whenion source 26 is used in the formation process for layer 2, then gassuch as Ar and/or C₂H₂ may be introduced into the ion source 26. In suchsituations, the ion source 26 may emit ions such as Ar ions, C ionsand/or H ions in beam B toward the layer formation area on thesubstrate.

As explained above, while Zr is used as a metal in the embodiments ofFIGS. 1-3, this invention is not so limited unless expressly claimed. Inthis respect, FIGS. 4-6 emphasize that the Zr in any of the embodimentsdescribed herein, or shown in FIGS. 1-3, may be replaced with Sn incertain example embodiments of this invention.

It is noted that any of the aforesaid materials for anti-etch layers 2(or 2′) may also be nitrided in certain example embodiments of thisinvention. In particular, nitrogen gas may also be used in thesputter-deposition process, for example, in order to at least partiallynitride the anti-etch layer in certain alternative embodiments of thisinvention. For example, and without limitation, the anti-etch layer 2may comprise or consist essentially of zirconium carbide oxynitride(e.g., ZrCON), zirconium carbide nitride (ZrCN), hydrogenated zirconiumcarbide oxynitride (e.g., ZrCON:H), and/or hydrogenated zirconiumcarbide nitride (e.g., ZrCN:H).

FIG. 8 is a cross sectional view of an example coated article, generallyspeaking according to an example embodiment. The anti etch layer 2 (or2′) may be made of or comprise one or more of the following materials incertain embodiments of this invention. Example materials, resistant toattacks by fluoride-based etchant(s), which may be used for layer 2 (or2′) include: nitrides of Al, Si, Nb, Cr and/or Ni, oxides of Al, Si, Ge,Mg, Nb, Mn, V, W, Hf, Ce, and/or Sn, carbides of Si and/or W, fluoridesof Mg, Ba and/or Ca, borides of Zr, Ni, Co and/or Fe, oxides of Mo, In,Ta, Ni, Nb, Cu, MoIn, MoTa, and/or NiCu, and oxynitrides of Mo, In, Ta,Ni, Nb, Cu, MoIn, MoTa, and/or NiCu. Other possible materials for anyanti-etch layer 2 (or 2′) herein include zirconium oxycarbide(ZrO_(x)C_(y)), tin oxycarbide (SnO_(x)C_(y)), zirconium nitride carbide(ZrN_(x)C_(y)), and/or tin nitride carbide (Sn_(x)NC_(y)). The DLCinclusive layer 3 is optional.

Moreover, in the FIG. 8 embodiment, the dielectric underlayer 4 isformed using flame pyrolysis in an atmosphere at or close to atmosphericpressure. Thus underlayer 4 formed in such a manner is of a materialsuch as silicon oxide (e.g., SiO₂). The use of flame pyrolysis to formthe underlayer(s) is advantageous in that the layer(s) formed usingflame pyrolysis may be formed in an ambient atmosphere which need not beat a pressure less than atmospheric. Thus, expensive sputtering or otherlow-pressure deposition systems need not be used to form this particularlayer(s). Moreover, another example advantage is that such an underlayerdeposited via flame pyrolysis has been found to further improve the etchresistance of the coated article by removing or reducing chemical orother defects on the glass surface. In particular, it is believed thatthe flame-pyrolysis deposited underlayer 4 removes or reduces chemicaldefects on the surface on which the anti-etch layer is directlyprovided. Such defects may lead to growth defects in the anti-etch layer2 which can be weak points more susceptible to etchant attack. Incertain respects, the flame-pyrolysis deposited layer (e.g., siliconoxide) 4 acts as a barrier layer to prevent certain defects and/orelements present at the glass surface (e.g., sodium, protrusions, etc.)from reaching and damaging the anti-etch layer. Thus, the removal orreduction of such defects via the use of the flame pyrolysis depositedunderlayer is advantageous in that etch resistance can be surprisinglyimproved.

For purposes of example, and without limitation, consider the followingexamples of flame pyrolysis which may be used in certain embodiments ofthe instant invention to form a layer(s) 4 on the glass substrate. Acombustion gas or fuel gas such as propane, and a silicon inclusivecompound such as SiH₄, organosilane, tetraethoxysilane (TEOS), HMDSO,organosiloxane, or the like, may be introduced into the flame in orderto cause a thin layer 4 of silicon oxide to form on the substrate 1,either directly or indirectly. The silicon oxide may include smallamounts of other elements in certain instances. Other examples of flamepyrolysis are described in U.S. Pat. Nos. 4,600,390, 4,620,988,3,883,336, and 5,958,361, the disclosures of which are herebyincorporated herein by reference.

FIG. 9 is a flowchart illustrating certain example steps performed inmaking the coated article of FIG. 8. First, after a glass substrate 1 isprovided, flame pyrolysis is used to deposit a base layer 4 of siliconoxide or the like on the substrate (S1). Then, the anti-etch layer 2 isformed on the substrate 1 over the base layer 4, via sputtering or thelike (S2). Then, optionally, a scratch resistant layer 3 of a materialsuch as DLC is formed on the substrate 1 over layers 2, 4.

EXAMPLES

The following examples are provided for purposes of example only and arenot intended to be limiting unless expressly claimed.

Examples 1 and 2 formed a Zr inclusive layer using a Zr sputteringtarget on a glass substrate. The Example 1 layer was of ZrO and had nocarbon, whereas the Example 2 layer was of ZrOC:H and thus did includecarbon. By comparing Examples 1 and 2, it can be seen that the provisionof carbon in the layer significantly improves corrosion resistance ofthe layer. The layers of Examples 1 and 2 were deposited on the glasssubstrate 1 using the following sputtering process parameters. Theparameters Ar, O₂, CO₂, C₂H₂, and N₂ illustrate how much gas flow wasused in the sputtering process in the sputtering chamber atmosphere foreach of these gases, in units of sccm. In each of Examples 1-2, a powerof 8 kW was used, 9 passes by the target were performed, the line ratewas about 15.4 inches per minute. The layer deposited in Example 1 endedup about 102 nm thick, whereas the layer in Example 2 ended up about 265nm thick.

Examples 1-2 Sputtering Process Parameters—Zr Target

Ar O₂ CO₂ C₂H₂ N₂ Ex. 1 200 75 0 0 0 Ex. 2 200 0 50 50 0

Thus, it will be appreciated that given the gases used in sputtering theZr inclusive layers in Examples 1 and 2, the Example 1 layer was of ZrOand had no carbon, whereas the Example 2 layer was of ZrOC:H sincecarbon dioxide and acetylene gases were used and thus did includecarbon. The Example 1 coated article had a visible transmission of about75%, whereas the Example 2 coated article had a visible transmission ofabout 66%.

Examples 1-2 were then exposed to a fluoride etchant for the same amountof time in order to compare the corrosion resistance of the two layers.Surprisingly, it was observed that after about 3 minutes of exposure tothe etchant, about 100% of the Example 1 layer had been removed whereasabout 0% of the Example 2 layer had been removed. Moreover, after about10 minutes of exposure to the etchant, only about 5% of the Example 2layer had been removed due to the etchant, mostly via pinholes. Thus, itcan be seen by comparing Examples 1 and 2, that the provision of carbonin the layer significantly improve corrosion resistance of the layer. Inparticular, the Example 2 layer with carbon was much more resistant tocorrosion than was the Example 1 layer without carbon.

Examples 3 and 4 are additional examples of certain embodiments of thisinvention, where Zr inclusive anti-etch layers 2 were deposited on aglass substrate 1 via sputtering using Zr sputtering targets. In each ofExamples 3-4, a power of 8 kW was used, 9 passes by the target wereperformed, the line rate was about 15.4 inches per minute. The layerdeposited in Example 3 ended up about 285 nm thick, whereas the layer inExample 4 ended up about 172 nm thick.

Examples 3-4 Sputtering Process Parameters—Zr Target

Ar O₂ CO₂ C₂H₂ N₂ Ex. 3 200 10 0 50 50 Ex. 4 200 25 0 50 50

Thus, it will be appreciated that given the gases used in sputtering theZr inclusive layers in Examples 3 and 4, each of the anti-etch layers 2of Examples 3 and 4 was of hydrogenated zirconium carbide oxynitride(e.g., ZrCON:H). The Example 3 coated article had a visible transmissionof about 21%, whereas the Example 4 coated article had a visibletransmission of about 57%. Examples 3-4 were then exposed to a fluorideetchant for the same amount of time in order to compare the corrosionresistance of the two layers. Surprisingly, it was observed that afterabout 3 minutes of exposure to the etchant, about 0% of the Example 3layer and about 0% of the Example 4 layer had been removed. Moreover,after about 10 minutes of exposure to the etchant, only about 5% of theExample 4 layer and 0% of the Example 3 layer had been removed due tothe etchant.

Examples 5 and 6 formed a Sn inclusive layer using a Sn sputteringtarget on a glass substrate. The Example 5 layer was of SnO (probably aversion of SnO known as SnO₂) and had no carbon, whereas the Example 6layer was of SnOC and thus did include carbon and did not includehydrogen. By comparing Examples 5 and 6, it can be seen that theprovision of carbon in the layer significantly improves corrosionresistance of the layer. The layers of Examples 5 and 6 were depositedon the glass substrate 1 using the following sputtering processparameters. The parameters Ar, O₂, CO₂, C₂H₂, and N₂ illustrate how muchgas flow was used in the sputtering process in the sputtering chamberatmosphere where the target was located for each of these gases, inunits of sccm. In Example 5 a power of 20 kW was used and in Example 6 apower of 5 kW was used. In each of Examples 5-6, 1 pass by the targetwas performed, and the line rate was about 15.4 inches per minute. Thelayer deposited in Example 5 ended up about 79 nm thick, whereas thelayer in Example 6 ended up about 45 nm thick.

Examples 5-6 Sputtering Process Parameters—Sn Target

Ar O₂ CO₂ C₂H₂ N₂ Ex. 5 250 550 0 0 0 Ex. 6 250 0 460 0 0

Thus, it will be appreciated that given the gases used in sputtering theSn inclusive layers in Examples 5 and 6, the Example 5 layer was of SnOand had no carbon, whereas the Example 6 layer was of SnOC since carbondioxide was used and thus did include carbon. The Example 5 coatedarticle had a visible transmission of about 74%, whereas the Example 6coated article had a visible transmission of about 70%.

Examples 5-6 were then exposed to a fluoride etchant for the same amountof time in order to compare the corrosion resistance of the two layers.Surprisingly, it was observed that after about 3 minutes of exposure tothe etchant, about 15% of the Example 5 layer had been removed whereasonly about 10% of the Example 6 layer had been removed. Thus, it can beseen by comparing Examples 5 and 6, that the provision of carbon in thelayer improved corrosion resistance of the layer. In particular, theExample 6 layer with carbon was more resistant to corrosion than was theExample 5 layer without carbon.

A flame pyrolysis deposited dielectric layer (e.g., silicon oxide) maybe formed between the glass substrate and the anti-etch layer in any ofExamples 1-6.

Examples 7-8 illustrate example advantages associated with the use of anunderlayer 4 of silicon oxide under an anti-etch layer 2 on a floatglass substrate 1. For Example 7, a MSVD SiO₂ layer about 100 Å thickwas deposited on a float glass substrate. An anti-etch layer of ceriumoxide was then deposited on the substrate over the SiO₂ layer, andfluoride based etch resistance testing was performed using Armor Etch.Comparing samples (Example 8) without the SiO₂ layer with samples(Example 7) with the SiO₂ layer, much less damage (primarily in the formof pinholes) was observed on the sample (Example 7) having the SiO₂layer under the anti-etch layer. Thus, the unexpected advantagesassociated with the use of the silicon oxide underlayer 4 are clear.

Embodiments Including Seed Layer(s)

The example embodiments described above have successfully providedcoated articles that are resistant to voluntary scratching and etching.It has been observed by the inventors of the instant application,however, that it is often difficult to form a DLC layer on an anti-etchlayer. For example, depositing DLC on an anti-etch layer(s) comprisingor consisting essentially of fluorine-doped tin oxide (e.g., SnO₂:F) hasbeen found to damage the anti-etch layer(s). In such instances, althoughthe mechanical durability may be increased by the inclusion of DLC, theresistance to etchants may be somewhat compromised. For example, theinclusion of DLC may weaken the anti-etch layers in whole or in part,e.g., by creating weak spots in the anti-etch layer(s) for instance,that are more susceptible to fluorine-inclusive etchants. Thus, althoughthe example embodiments described above have been successful inproviding coated articles that are resistant to abrasion (e.g.,scratches) and chemical etching (e.g., by fluorine-inclusiveetchant(s)), the inventors of the instant application have realized thatfurther improvements are possible and would be desirable. Accordingly,certain example embodiments address this challenge, e.g., by providingimproved coated articles. Such improved coated articles may have coatingstacks that have an improved resistance to chemical etching (e.g., byfluorine-inclusive etchant(s)) and/or improved resistance to scratching,e.g., by providing DLC to the coated article in a manner reduces thenegative effects on the anti-etch layer(s).

The inventors of the instant application have discovered that providinga seed layer between the anti-etch layer(s) and the DLC facilitates thedeposition of the DLC while also protecting the anti-etch layer(s). Forexample, such a seed layer may provide a better adhesion target for theDLC and/or absorb some of the damage that otherwise would have been doneto the anti-etch layer(s). To this end, FIG. 10 is a cross sectionalview of a coated article according to another example embodiment of thisinvention. Similar to the example embodiments described above, thecoated article shown in FIG. 10 may include a glass substrate 1. One ormore anti-etch or HF resistant layer(s) 2″ and a DLC layer 3 aresupported by the glass substrate 1, with the anti-etch or HF resistantlayer(s) 2″ being closer to the substrate 1 than the DLC layer 3. TheDLC 3 may be about 1-10 nm thick, more preferably about 3-7 nm thick,and still more preferably about 3-5 nm thick.

To facilitate the adhesion of the DLC to the overall layer structureand/or to help protect the anti-etch or HF resistant layer(s) 2″, a seedlayer 5 is provided between the DLC layer 3 and the anti-etch or HFresistant layer(s) 2″. In certain example embodiments, the seed layer 5may be relatively thin compared to the anti-etch or HF resistantlayer(s) 2″ and the DLC layer 3. For instance, in certain exampleembodiments, the seed layer 5 may be about 5-100 angstroms thick, morepreferably about 7 to 75 angstroms thick, and still more preferablyabout 10-50 angstroms thick. Of course, it will be appreciated thatother thicknesses smaller or lager or within sub-ranges of these rangesmay also be chosen.

In certain example embodiments, the seed layer 5 may comprise or consistessentially of silicon nitride (e.g., Si₃N₄ or other suitablestoichiometry). The inventors realized that silicon nitride could beused as or in the seed layer 5, as DLC will grow on it and because it isa hard, solid substance with a crystallographic structure that helpsreduce the likelihood of damage to the anti-etch or HF resistantlayer(s) 2′. It will be appreciated that other compositions may be usedinstead of silicon nitride in connection with seed layer 5.

FIG. 11 is a cross sectional view of a coated article according toanother example embodiment of this invention. The example coated stackshown in FIG. 11 is like that shown in FIG. 10, except that, in thelayer stack, the HF resistant layer 2″ comprises or consists essentiallyof fluorine-doped tin oxide (e.g., SnO₂:F). The fluorine-doped tin oxidethat comprises or essentially consisting the anti-etch or HF resistantlayer(s) 2″ may be formed by any suitable technique. For example, SnO₂:Fmay be formed via conventional combustion vapor deposition (CVD), flameCVD, spray pyrolysis, etc. In certain example embodiments, thefluorine-doped tin oxide layer 2″ of FIG. 11 may be fairly thick,especially when compared to the seed layer 5 and the DLC layer 3. Forinstance, in certain example embodiments the fluorine-doped tin oxidelayer 2″ may be about 50-450nm thick, more preferably about 100-400 nmthick, and still more preferably about 150-350 nm thick. Of course, itwill be appreciated that other thicknesses smaller or lager or withinsub-ranges of these ranges may also be chosen. It also will beappreciated that other compositions may be used instead offluorine-doped tin oxide in connection with the anti-etch or HFresistant layer 2″.

FIG. 12 is a cross sectional view of a coated article according toanother example embodiment of this invention. Similar to above, one ormore optional base layer(s) or underlayer(s) 6 may be provided inconnection with certain example embodiments. As noted above, providingsuch a base layer(s) or underlayer(s) 6 may provide further surprisingand/or unexpected beneficial results, e.g., when silicon oxide (e.g.,SiO₂ or other suitable stoichiometry) is deposited.

The optional base layer(s) or underlayer(s) 6 may be a low-E (lowemissivity) color suppression stack. For example, as shown in theexample coated article of FIG. 13, a pyrolitically deposited low-E colorsuppression stack 6 may comprise a first sub-layer 6a comprising orconsisting essentially of silicon oxide (e.g., SiO₂ or other suitablestoichiometry) and a second sub-layer 6b comprising or consistingessentially of tin oxide (e.g., SnO₂ or other suitable stoichiometry)closer to the substrate 1. In certain example embodiments, the firstsub-layer 6a comprising or consisting essentially of silicon oxide maybe about 5-35 nm thick or, more preferably, about 10-30 nm thick. Incertain example embodiments, the a second sub-layer 6b comprising orconsisting essentially of tin oxide may be about 5-35 nm thick or, morepreferably, about 10-30 nm thick. It will be appreciated that more orfewer layers or different compositions may comprise such a pyroliticallydeposited low-E color suppression stack, that a low-E color suppressionstack need not necessarily be pyrolitically deposited, etc. It also willbe appreciated that the base layer(s) or underlayer(s) 6 need notnecessarily be a low-E color suppression stack, at all.

FIG. 14 is a cross sectional view of a coated article according toanother example embodiment of this invention. FIG. 14 is similar to FIG.11, except that instead of the anti-etch or HF resistant layer(s) 2′″ inFIG. 14 comprises or consists essentially of cerium oxide (e.g., CeO₂ orother suitable stoichiometry) and is provided in place of anti-etch orHF resistant layer(s) 2″ of FIG. 11 which, as noted above, comprises orconsists essentially of fluorine-doped tin oxide. The anti-etch or HFresistant layer(s) 2′″ of FIG. 14 may have the same or differentthickness as the fluorine-doped tin oxide layer(s) 2″ of FIG. 11.

FIG. 15 is a flowchart listing certain example steps performed in makingthe coated article of FIG. 12 according to an example embodiment of thisinvention. A base layer is deposited on a substrate (S4), e.g., via apyrolytic process such as CVD, flame deposition, or the like. Then, ananti-etch layer is formed over the base layer (S5), e.g., via sputteringor the like. A seed layer is formed over the base layer (S6). Finally, ascratch resistant layer of DLC is formed on the substrate (S7), with theseed layer facilitating the adhesion of the DLC on the overall stackand/or helping to protect the anti-etch layer.

While a particular layer or coating may be said to be “on” or “supportedby” a substrate or another coating (directly or indirectly), otherlayer(s) and/or coatings may be provided therebetween. Thus, forexample, a coating may be considered “on” and “supported by” a substrateeven if other layer(s) are provided between layer(s) and the substrate.Moreover, certain layers or coatings may be removed in certainembodiments, while others may be added in other embodiments of thisinvention without departing from the overall spirit of certainembodiments of this invention.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1. A method of making a coated article, the method comprising: providinga glass substrate; forming an anti-etch layer on the glass substrate,the anti-etch layer consisting essentially of fluorine-doped tin oxide;ion beam depositing a scratch-resistant layer comprising diamond-likecarbon (DLC) on the glass substrate over the anti-etch layer; andforming a seed layer between the anti-etch layer and the layercomprising DLC, the seed layer facilitating adhesion of the layercomprising DLC and/or protecting the anti-etch layer from damage duringthe ion beam depositing of the layer comprising DLC.
 2. The method ofclaim 1, wherein the seed layer comprises silicon nitride.
 3. The methodof claim 1, wherein the anti-etch layer is deposited via flamepyrolysis, combustion vapor deposition, flame deposition, or spraypyrolysis.
 4. The method of claim 1, further comprising forming a baselayer or underlayer on the glass substrate, wherein the anti-etch layeris deposited over the base layer or underlayer.
 5. The method of claim4, wherein the base layer or underlayer is a low-E color suppressionlayer stack.
 6. The method of claim 5, wherein the low-E colorsuppression layer stack comprises a layer of tin oxide on the glasssubstrate and a layer of silicon oxide provided on the tin oxideopposite the glass substrate.
 7. The method of claim 1, wherein thecoated article is a window.
 8. The method of claim 1, wherein the coatedarticle has a visible transmission of at least about 50%.
 9. The methodof claim 1, wherein the anti-etch layer is resistant tofluorine-inclusive etchants.
 10. The method of claim 1, furthercomprising forming a base layer or underlayer on the glass substrate,wherein the anti-etch layer is deposited over the base layer orunderlayer, and wherein the seed layer comprises silicon nitride. 11.The method of claim 1, wherein the anti-etch layer is about 150-350 nmthick, wherein the seed layer is about 1-5 nm thick, and wherein thelayer comprising DLC is about 3-5 nm thick.
 12. A method of making acoated article, the method comprising: providing a glass substrate;forming a base layer or underlayer on the glass substrate; forming ananti-etch layer over the base layer or underlayer, the anti-etch layercomprising at least one of fluorine-doped tin oxide and cerium oxide;ion beam depositing a layer comprising diamond-like carbon (DLC) on theglass substrate over the anti-etch layer; and forming a seed layerbetween and contacting both the anti-etch layer and the layer comprisingDLC, the seed layer comprising silicon nitride.
 13. The method of claim12, further comprising facilitating, via the seed layer, the ion beamdepositing of the layer comprising DLC.
 14. The method of claim 12,wherein the seed layer helps protect the anti-etch layer from damageduring the ion beam depositing of the layer comprising DLC.
 15. Themethod of claim 12, wherein the base layer or underlayer is a low-Elayer stack.
 16. The method of claim 15, wherein the low-E layer stackcomprises a layer of tin oxide on the glass substrate and a layer ofsilicon oxide provided on the tin oxide opposite the glass substrate.17. The method of claim 12, wherein the coated article has a visibletransmission of at least about 50%.
 18. The method of claim 12, whereinthe anti-etch layer is resistant to fluorine-inclusive etchants.
 19. Themethod of claim 12, wherein the anti-etch layer consists essentially offluorine-doped tin oxide.